Rituximab for Refractory Myasthenia Gravis in a Pregnant Patient (P2.165)

Objective: To report the first ever case of successful pregnancy outcome in a patient who received Rituximab infusion for refractory Myasthenia Gravis Background: Rituximab (RTX) is a chimeric Immunoglobulin G1 monoclonal anti-CD-20 antibody. Traditionally, RTX has been used for hematological malignancies and autoimmune disorders. Recently, there have been reports which have shown benefit of RTX in refractory Myasthenia Gravis (MG). There is little data available regarding safety of RTX during pregnancy. Method: 23 years-old female suffering from refractory MG (non-responsive to thymectomy, plasmapharesis, intravenous immunoglobilins and mycophenolate) was started on RTX infusion (375 mg/m2) with daily pyridostigmine maintenance. After two infusions, she demonstrated a favorable response. She conceived six months after the second infusion. . Result:Pregnancy was complicated by Pre-Eclempsia at 39 weeks. Spontaneous vaginal delivery of a healthy 3039 g boy at 39 weeks. Post-partum period was complicated by a single eclemptic seizure which responded to intravenous magnesium. Baby showed no evidence of weakness or immunosuppression on follow up visits. Conclusion:We present the first case of a successful pregnancy in a patient treated with RTX infusion for refractory MG. Auto-reactive B cells are appropriate candidates for targeted drug therapy as they play an important role in the pathogenesis of MG. RTX global drug safety database contains only 153 pregnancy outcomes out of which none of them were MG patients. There were 90 live births with 22 preterm deliveries, 33 spontaneous abortions, 1 still birth and 1 maternal death. There were higher rates of preterm deliveries and first trimester losses compared to general population. There were two reports of congenital anomalies (club foot and cardiac malformation). Despite lack of strong evidence of teratogenesis, limited cohort size prevents drawing conclusions regarding safety of RTX. It is still recommended to use effective contraception during and for 12 months after treatment. Disclosure: Dr. Girotra has nothing to disclose. Dr. Baki has nothing to disclose. Dr. Grover has nothing to disclose.